Solutions must be applied to every situation individually

If the goal was to stop cars from entering the court, it would fulfill its purpose under normal circumstances. People trying to break the door by driving through with a truck would not consider the door as a great obstacle. Looking at the issue that one side of the door was open most of the time, but locked at specific dates, raises another interesting question: What was the purpose of locking the door? The door is not high enough to keep people from jumping over it. If the owner just wanted to indicate, that he doesn't like anyone to play there, but doesn't care if someone does - then it fulfilled its purpose. If he really wanted to keep people from playing he either didn't want to spend more money on building higher walls, he didn't want to build higher walls because the would look bad or he just didn't think of someone climbing over closed doors. Of course, the intention of locking the door could have also been to have legal possibilities to sue people using the court without asking. Or, he just didn't think anything when leaving the place locked or unlocked. 

As you can see, security must be applied individually to each situation, purpose and financial situation. Therefore finding appropriate solutions after doing an assessment can only be done in cooperation with the responsible persons to ensue that the solution really fits the needs and means available.